This invention relates to a fume extractor device for attachment adjacent a filling orifice of a container.
Many chemicals are supplied in cylindrical drums, typically of about 200 liters capacity, which are closed by a stopper screwed into an orifice at one end. To withdraw contents from the drum it is normal practice to stand the drum on end with the orifice at the top, remove the stopper, insert a dip tube and pump out the contents. Unfortunately during this process vapors from the chemical in the drum escape into the atmosphere when the stopper is first removed and later from the annular space around the dip tube. These vapors can constitute an environmental hazard if they are inflammable, toxic, corrosive or have an unpleasant smell. It is customary to attempt to minimize this hazard by placing the open end of a large diameter flexible pipe which is attached to a fume removal system close to the orifice, but this practice does not entirely prevent the escape of inflammable, toxic, corrosive or unpleasant vapors into the surrounding atmosphere. Evaporation of liquid adhering to the surface of the dip pipe upon removal from the drum may create further such hazard.
Steam removal is frequently employed to extract final traces of drum contents, but such removal frequently has the disadvantages that the normal large-diameter conduit of a steam extraction system cannot be precisely located and is unable fully to cope with the steam and vapor from the drum.
Similar problems can be experienced when filling such drums due to air forced out of the drum containing chemical vapor.